1. Field of the Invention
The invention relates to an energy supply device of a melting tank with an electrode plane in the melting tank and a converter for voltage supply of the electrode plane.
2. Description of the Prior Art
In a conventional energy supply device of an optical melting tank the energy feed to the melting tank takes place over the crown of the melting tank by combustion of a fossil energy carrier and furthermore, in the bottom zone of the melting tank by electrodes. The electrodes are arranged in several electrode planes and are supplied with alternating current at a medium frequency of 10 kHz from several converters, in which arrangement to each electrode plane there is associated in each case a converter.
The electrode planes are connected to the converters over energy supply lines and control lines, which are permanently wired. If a converter fails by reason of a technical defect, then the corresponding electrode plane can no longer be operated. Through the absent energy feed of the corresponding electrode plane there occur temperature unbalances in the optical melting tank, so that the tank altogether can no longer be operated. The operation of the entire optical melting tank must consequently be interrupted in order to change or replace the defective converter. Since this latter is firmly wired with the electrode plane, it is necessary for a coworker with training in electricity to disconnect the defective converter either to repair it or to replace it. This complicated repair leads to down times lasting from a few hours to several days.
The problem of the invention is to further develop an energy supply device of a melting tank in such manner that on failure of an individual converter the down time of the entire melting tank is minimized, and maintenance operations are simplified.
This problem is solved by providing a separatable plug connection between an electrode plane and a converter.
If, in this energy supply device, a converter fails, then same can be electrically separated from the electrode plane by simply pulling-off the plug connection. The severing of the connection can be performed by semi-skilled personnel, without an especially trained electrician being required for the purpose. The separation occurs within an extremely short time and the defective converter can be either repaired or exchanged for a new converter.
By the separation of the current supply line between the converter and in a maintenance operation or a repair, the electrode plane safety is enhanced, since the converter is electrically completely separate from the electrode plane.
In an especially advantageous mode of execution of the energy supply device, the latter comprises a spare converter which likewise can be replaced. If a failure of a converter occurs here, then the supply line between the defective converter and the electrode plane can be rapidly cut off, and the supply line of the electrode plane can simply be changed over to a connection to the reserve converted. It is not necessary, therefore, immediately to repair or replace the defective converter. The down time of the melting tank is now only the time required for the changeover from the defective converter to the spare converter. There is thus ensured a virtually trouble-free operation of the melting tank.
For the further enhancement of the operating security, in a further form of execution the plug connection is equipped with an end contact. The end contact is actuated when the plug connection between the converter and the electrode plane is completely established. The operation of the converter is switched over the end contact, in which process the converter is switched free of voltage and current as soon as the plug connection is cut off. Therewith the corresponding plug connection becomes free of voltage and current, even before the plug connection is completely separated, so that in the event of an inadvertent separation of the plug connection the operating safety of the working personnel is guaranteed.
The end contact can be a mechanical switch or a magnetic switch, such as a reed relay. The end contact can be arranged directly within the plug connection or bordering on this.
If the plug connection is executed as a coaxial plug connection, then the internal conductor is shielded by the outer conductor.
For the further improvement of the safety of operation, the part of the plug connection that leads to the energy-feeding converter is executed as a plug socket. Thereby an inadvertent contacting of current-conducting lines is precluded.
In an especially advantageous form of execution each supply line between a plurality of electrode planes and a corresponding number of converters is connected by a separatable plug connection. Thereby the melting tank can be completely uncoupled from the energy feed of the converters. By the complete separating of the melting tank from the energy feed, the operating safety in the maintenance of the melting tank can be enhanced. There is also possible a complete exchanging of the melting tank or of the converters without any major electrical installation operations.
By the providing of a single spare converter, it is possible to replace the failing converter among the plurality of converters, with the reserve converter, in which operation the down time of the melting tank is further substantially reduced. Since with a plurality of converters only a single spare converter is provided as a reserve, the investment costs and maintenance costs are reduced.
If the plug sockets that are connected with the converters are arranged adjacently to one another, the clarity over the plug connection between the converters and the electrode planes is improved. Therewith there is likewise improved the operating safety and dependability of the energy supply device. Through the central arrangement of the plug connection even semi-skilled personnel can establish or release the plug connection.
For the further improvement of clarity, the plug sockets are grouped in each case adjacently to one another, for example according to functional units of the electrode planes. These functional units of electrode planes are, for example, the use unit xe2x80x9ctankxe2x80x9d, the use unit xe2x80x9ccruciblexe2x80x9d and the use unit xe2x80x9clynchingxe2x80x9d.
In an especially advantageous mode of execution of the energy supply device, the control lines between each electrode plane and its allocated converter likewise are connected over separatable plug connections. Thereby the separating of the converter from the electrode plane is further facilitated.
For the further improvement of clarity, in each case beside a plug socket for the energy supply to the electrode planes there are arranged one or several control plug connections. There, one side of a control plug connection is connected to a control line which is brought together with a plug control line of the electrode plane. Thereby the energy supply line connections and control connections for the converter lie immediately next to one another, and likewise do the supply line and the control lines for the electrode plane, this facilitating the allocation of the connecting element, whereby operating safety is enhanced.